I'm Bonk, and I've done a quick review of your PR.

Summary: Adds a GC stress test mode (--gc-stress / WORKERD_GC_STRESS=1) that forces full V8 GC after microtasks and at awaitIo continuations, with Bazel test variants and just-recipes.

One low-severity finding posted as an inline comment:

1. [LOW] The freelist bypass in src/workerd/jsg/wrappable.c++:184 is not #ifndef NDEBUG-gated, while the GC injection points in io-context.c++ are. In release builds, this means the freelist skip has cost (extra cppgc allocations) but no benefit (GC isn't actually forced at continuations). Suggested wrapping it in #ifndef NDEBUG for consistency, or adding a comment explaining the intent.

Overall the implementation is clean and well-documented. The thread-scope flag follows the established predictableMode pattern, the Bazel variant generation is properly tagged off-by-default, and the static const env-var caching in isGcStressModeForTest() is a nice touch for subprocess use cases. No backward compatibility, security, or memory safety concerns.

github run

The generated output of @cloudflare/workers-types matches the snapshot in types/generated-snapshot 🎉